SHEEP (Ovis).  GOAT (Capra).

1.  Muzzle hairy except between 1.  Muzzle entirely hairy.
   and just above the
   nostrils.

2.  Interdigital glands on all 2.  Interdigital glands, when
   the feet. present, only on fore feet.

3.  Suborbital gland and pit 3.  Suborbital gland and pit
   usually present. never present.

4.  No beard nor caprine 4.  Male with a beard and
   smell in male. caprine smell.

5.  Horns with coarse transverse 5.  Horns with fine transverse
   wrinkles; yellowish striations, or bold knobs
   or brown; sub-triangular in front; blackish; in male
   in male, spreading outward more compressed or angular,
   and forward with a sweeping backward
   circular sweep, points with a scythe-like curve or
   turned outward and forward spirally, points turned upward
                                     and backward.

These features are distinctive as between most sheep and most goats, but the Barbary wild sheep (Ovis tragelaphus) has no suborbital gland or pit, a goat-like peculiarity which it shares with the Himalayan bharal (Ovis nahura), in which the horns resemble closely those of a goat from the eastern Caucasus called tur (Capra cylindricornis), which for its part has the horns somewhat sheep-like and a very small beard.  This same bharal has the goat-like habit of raising itself upon its hind legs before butting.

Both groups are a comparatively late development of the bovine stock, as they do not certainly appear before the upper Pliocene of Europe and Asia, and even at a later date their remains are not plentiful.  Goats appear to have been rather the earlier, but are entirely absent from America.

The number of distinct species of sheep in our fauna is a matter of too much uncertainty to be treated with any sort of authority at this time.  Most of us grew up in the belief that there was but one, the well-known mountain sheep (Ovis canadensis), but seven new species and sub-species have been produced from the systematic mill within recent years, six of them since 1897.  It is no part of the purpose of the present paper to dwell upon much vexed questions of specific distinctness, and it will only be pointed out here that the ultimate validity of most of these supposed forms will depend chiefly upon the exactness of the conception of species which will replace among zoologists the vague ideas of the present time.  Whatever the conclusion may be, it seems probable that some degree of distinction will be accorded to, at least, one or two Alaskan forms.

As sheep probably came into America from Asia during the Pleistocene, at a time when Bering’s Strait was closed by land, it might be expected that those now found here would show relationship to the Kamtschatkan species (Ovis nivicola); and such is indeed the case, while furthermore, in the small size of the suborbital gland and pit, and in comparative smoothness of the horns, both species approach the bharal of Thibet and India, which in these respects is goat-like.